Abnormal gait patterns are common in people with cerebral palsy. A surgical intervention to diminish internal rotation during gait in the cerebral palsy population has included soft tissue procedures and rotation osteotomies. One common procedure is varus rotation osteotomy, VRO. We report here on the results for 37 people with cerebral palsy who were at least 3 years old, cooperative and able to follow directions. The average age at the pre-operative test stage was 8.7+3.3 years. There were 14 males and 23 females. Thirty-five were diplegics and two were quadraplegics. Each was tested pre-operatively, at six months post-operative and 12 months post-operative. The mean difference curve along with the 95% confidence interval about the difference was calculated using a bootstrap technique. The depiction of the bootstrapped curves is compared with the use of the maximum value for comparisons.